Consumer acceptance of beer products having reduced alcohol concentrations is a well established market place phenomenon. Most of the present day processes for producing alcohol-reduced beverages however, are based on technology which originated during the temperence and prohibition eras in North America.
Historically, processes for the production of alcohol-reduced beers typically entailed one of three basic approaches. The first such approach involved the use of distillation apparatus adapted to drive-off alcohol from an alcoholic beer by boiling the beer, in some instances under partial vacuum in an attempt to minimize the amount of heat damage incurred during such processing of the beverage. Variations on this general theme are disclosed, inter alia, in U.S. Pat. Nos. 613,915; 662,172; 721,383; 935,814; 977,303; 1,017,086; 1,084,833; 1,171,306; 1,202,662; 1,238,577; 1,234,811; 1,264,564; 1,286,315; 1,290,192; 1,302,549; and, 1,311,421. With the end of prohibition, attempts at boiling beer, especially at ambient atmospheric pressures, to drive-off the alcohol contained therein, were abandoned because the resulting products were not salable in the highly competitive, deregulated market place. The flavour of the boiled beer was compromised to the extent that it was not palatable. Accordingly, the processes disclosed in the above-listed patents are only of historical interest, although more recent refinements have been brought to bear on this general approach to the problem of reducing the alcohol content of regularly-brewed beers, (see for example U.S. Pat. No. 4,256,920 or UK Patent No. 2,113,712). All such distillation processes, however, remain disadvantageously energy intensive and inherently involve additional capital and operating expenditures which can seriously compromise their usefulness in a competitive, commercial scale brewery operation. Even when such processes are carried out with a de-esterizing column arranged in tandem with the dealcoholizing apparatus in order to return desirable volatiles to beer, important flavour cogeners are nonetheless lost along with the alcohol. Moreover, the relatively high temperatures used to distill the alcohol from the beer, almost invariably resulted in unacceptable damage to the flavour of the resulting beverage.
The second historical approach involved interrupting the fermentation of a conventionally prepared brewer's wort before the alcohol concentration developed beyond about 1-2%. The interruption can be achieved by filtering to remove the yeast and pasturizing the partially fermented wort. The resulting products, however, invariably have a strong, undesirable "worty" flavour.
The third approach was to utilize an unfermented brewer's wort as an alcohol-free beer, without any fermentation whatsoever. These products have an even stronger "wort" flavour.
More recently, the trend in the production of alcohol-reduced beers has included more progressive and diverse approaches to the problem. One example of such an approach is disclosed in UK No. 1,447,505, wherein there is described a reverse osmosis teatment which is adapted to dealcoholize a regularly-brewed beer. Unlike the distillation processes, such a reverse osmosis treatment does not cause heat damage to the beer flavour. However, the process remains subject to the other disadvantages mentioned above in respect of the distillation processes, in that reverse osmosis installations are very capital intensive. In addition, the nature of the reverse osmosis treatment is such that important flavour cogeners of the beer are lost along with the alcohol even though the amounts lost are less than those lost during dealcoholization with distillation apparatus.
Another approach involves the use of aerobic fermentations, while yet another calls for the use of specialized yeast strains (e.g. S. ludwigii), which do not produce large quantities of alcohol under normal fermentation conditions because the yeast is unable to utilize maltose.
One of the objectives of the present invention is to provide a brewing process adapted to produce a high extract-to-alcohol beer which is particularly useful both in and of itself, or as an intermediate in the production of alcohol-reduced beers, which process readily lends itself to established commercial scale brewery practices without requiring any extraordinary capital outlay or engendering any unusual maintainance costs. Moreover, it is a further object of the present invention to produce, by way of this novel process, a quality beer having a reduced alcohol concentration which beverage is subject neither to the undesirably worty flavour associated with partially fermented or entirely unfermented beers, as aforementioned, nor to the undesirable flavour problems characterizing those dealcoholized beers from which the alcohol has been removed by distillation in the traditional manner, or by way of reverse osmosis.